Your suggestions allows for each player to make a choice; to either finish in solo mode or to take a drop in reputation. Then it makes provisions for the last player left on the course to drop, without having to make the same choice.
I have read it many times, far too many actually. I only dismissed it after careful consideration. It is problematic in its concept, implementation, and effectiveness.
I certainly agree with the option to choose to continue in solo mode or face a drop in reputation, but this would have to be the same for all players regardless of whether they are the first to drop from a round, or the last one left there.
Short of that, taking away the option to exit the round and forcing each and every player to finish each and every round is the only viable option. There is NO true way to determine the validity of a dropped round. This was the cause of the massive failure of the rep feature the first time around, and it will repeat itself if they try it again. It doesn't get any more fair than to give everyone the same options. And again, once sand-baggers know that they have to resume a round and that they can not prevent the score from posting, their behaviors will change. This is the truest goal.